U.S. Pat. No. 5,743,070 issued Apr. 28, 1998 to Hershey Lerner and Dana J. Liebhart (herein "the SP Patent") discloses a packaging system which is enjoying significant commercial success. With the machine of the SP Patent, webs of side connected bags are used. Each web is an elongated, flattened, plastic tube which includes a top section which itself is essentially a tube. In use the top section is fed over a mandrel and past a slitter which separates the top section into two upstanding lips. The lips are grasped by unique belts that are fed along divergent paths of travel into parallel paths through a load station. The unique belts are described more fully in U.S. Pat. No. 5,722,218 issued Mar. 3, 1998 to Hershey Lerner under the title Plastic Transport System (herein "the Belt Patent"). The disclosures of the SP Patent and the Belt Patent are incorporated by reference.
Each web includes side connected bags which depend from the lips. As a web is fed along its path of travel through a machine of the SP Patent (the SP Machine), lines of weakness interconnecting sides of adjacent bags are ruptured to leave individual webs depending from the lips.
As the belts diverge, the gripped lips are separated from the depending bags along lines of weakness to the extent necessary to cause the bags to span the space between the parallel paths in a generally rectangular opening.
A problem that has manifested itself, is that the bags have not consistently opened into rectangular configurations, but rather assume other trapezoidal shapes. Moreover, the trapezoidal shapes assumed vary from web to web and indeed on occasions from bag to bag within the same web.
While the failure to open into a truly rectangular configuration can be tolerated with some products, there are other products which make the system of the SP Machine unacceptable. For example, if one is seeking to tightly package sponges each in the shape of a rectangular solid, it may be impossible to insert the products into bags other than those opened to a rectangular configuration of the precise dimension required each to receive a sponge and then produce a tight fitting bag around it.